The purpose of this study was to obtain a better assessment of the Patras, Greece, air quality, in terms of the primary pollutants total suspended particulates (TSPs) and sulfur dioxide (SO2), because limited and short-duration measurements have been conducted in the past. Installation and operation of a mobile air monitoring station at two different locations in the Patras downtown area and one location in the outskirts of the city was undertaken and covered the periods July 1, 1994-January 30, 1995; March 18-August 23, 1995; and April 19-July 27, 1996, respectively. For both pollutants measured at each location, the monthly average concentrations and typical weekly variation of daily averages, as well as the diurnal variations and frequency concentration distributions in each month of the monitoring periods, were calculated and are presented in bar diagrams. The annual and winter period medians and the annual 98th percentile were also calculated and are compared with the limit and guide values provided by the European Economic Community Council Directive 80/779/EEC. In addition, comparison of SO2 values is made with the limit values adopted by the more recent Directive 1999/30/EC. It was found that the TSP and SO2 levels at all locations were very low and were lower than the levels found in Thessaloniki and Athens, Greece. An attempt to explain what had been measured is also undertaken. The data presented are considered essential for future reference and comparison purposes.